It is known to provide traction-increasing attachments for the power-driven wheels of automotive vehicles, e.g. U.S. Pat. Nos. 963,667 (Vergote), 1,588,065 (Thomsen), and 4,036,272 (Lee). But none is known which has at least one rigid cleat-carrying member diametrically spanning the face of a conventional disk-type wheel and attached thereto by an easily and quickly mountable and demountable member diametrically backing said rigid member and anchored to said wheel by fingers extending through and expanded behind conventional slots in the margins of said wheel. It is the principal object of the invention to provide such a device. Other objects and advantages will appear as the following detailed description proceeds.